# score-over-v1: key ceremony transcript

Everything below is also in `circuit.json` (field `ceremony`). Times are UTC.

| | |
|---|---|
| Circuit | `score-over-v1` = zk-kit `threshold_b10_n` (threshold, {"bits":10,"nonce":true}), 271 constraints |
| circuitId | `0xa85030dcc31080ea2946cf9ee8662bd225736caf3c6c5d2f8ad64a881583a979` = keccak256("score-over-v1") |
| Public signals | `commitment`, `threshold`, `nonce` |
| vkHash | `0xa67ad431ce9e0ec172c16e12b7040d05cf5b55fec71144203008d59ff638fa37` = keccak256(JCS(verification_key.json)) |
| ceremonyContributions (registry) | 1 |

## Phase 1: public Powers of Tau

The PSE Perpetual Powers of Tau (80 participants, closed with a pre-announced Ethereum randao
beacon), response 0080 prepared for phase 2 and truncated to 2^9.

| | |
|---|---|
| URL | https://pse-trusted-setup-ppot.s3.eu-central-1.amazonaws.com/pot28_0080/ppot_0080_09.ptau |
| Size | 683,154 bytes |
| blake2b-512 | `33ccbcacd7c43238b540f8dd7f68b4acac6be3a1fe2e695d55aea291172d30ddc8056c2851f5660b5e795550f300660042072254813d1558dc4d5a7192eae9b6` |
| sha256 | `67e59e346767e179a5bd88b4789a56ce376708244c01a32b520ee208dbfb2595` |
| Header power | 2^9 (read from the file header) |
| S3 ETag | `69d89d14fb047514a1eb6c82ffd5a718` (last modified Tue, 09 Apr 2024 07:02:55 GMT); md5 matches |
| Downloaded | 2026-09-27T06:12:41.730Z |

PSE publishes no hash list for the prepared files, so the checks above are what could be made: the
header, the byte count, and the S3 multipart ETag recomputed from the bytes (a transport check, not
an authenticity check). snarkjs's full powers-of-tau verification was not run: it did not finish in
10 minutes even for the 2^8 file on the build machine. Download the file yourself and compare the
blake2b-512 before you rely on it.

## Phase 2

1. **Initial key** `_0000` = snarkjs `zkey new` of `score-over-v1.r1cs` on the phase-1 file. It is
   deterministic; anyone can recreate it (169,704 bytes, blake2b-512
   `98fd99f32ad311d74a5f92aaf5eb2ec9755f1fabeed1987be766869b222f481c764af1d6153d6c763c9aa807c06ecdedfd2ad617e83bf3bbdc9eae19602cb344`).
2. **Contribution #1: Super Wallet (SeoulLabs) phase-2 contribution**, 2026-09-27T06:12:44.628Z to 2026-09-27T06:12:44.713Z.
   Contribution hash:

   ```
   79ac91b94989b077914a9ca07198c583884ba68cf1dc20358c9a8bb2fe0b89c21b00b213679c068c5ac875b5694d8edada143f4af493db39caca1fdda0683b6a
   ```

   Entropy: 64 bytes from the operating system CSPRNG (`node:crypto` randomBytes), passed in
   memory to snarkjs, which mixes in its own random bytes. It was not written to disk, a log or a
   terminal, and the process has exited. All seven circuits of ceremony batch 2 were contributed in one
   run that finished at 2026-09-27T06:13:03.218Z.
3. **Beacon.** The rule, fixed in `zk-kit/scripts/production-ceremony.ts` before the run: after
   every contribution has finished, take the latest Xphere mainnet block whose timestamp is later
   than that moment, and apply its hash with 2^10 iterations (snarkjs `zkey beacon`).

   | | |
   |---|---|
   | Chain | Xphere mainnet, chain id 20250217 (read from https://en-hkg.x-phere.com) |
   | Block | 49689564 |
   | Block hash | `0xf881b8862fb95d63b2269b5a6e6ae228156d78250e72c9c7129901b460d820de` |
   | Block time | 2026-09-27T06:13:14.000Z (fetched 2026-09-27T06:13:13.528Z) |
   | Iterations | 2^10 |
   | Beacon contribution hash | `2afef3650dafb3ae431cbbe61a785ecba04f132d9d8cdd1af6a012df9f33b8c437b102534926d4b28f699e83e6564c4594fb331bb02d044d298365e492002638` |

   Check the block: `curl -s -X POST -H 'content-type: application/json' --data '{"jsonrpc":"2.0","id":1,"method":"eth_getBlockByNumber","params":["0x2f633dc",false]}' https://en-hkg.x-phere.com`
   and compare `hash`, or open https://xp.tamsa.io/block/49689564.

## What this ceremony does and does not give you

A Groth16 phase 2 is sound if **at least one** contributor destroyed their randomness. This key has
**one** contributor, Super Wallet, so its soundness rests on Super Wallet having done so. The public
beacon makes the final key depend on a value nobody knew when the contribution was made, but it is
public and adds no secret: it does not replace a second, independent contributor. The block number
was not announced in advance; the rule for picking it was fixed in the script, and the block came
after the contribution. The registry records `ceremonyContributions = 1` as it is.

**An institution that wants to add its own contribution** takes `score-over-v1.zkey` (this key; the
contribution chain inside it continues), checks it with `zk-kit verify-ceremony`, runs
`zk-kit contribute`, and hands the result back; Super Wallet then applies a new, pre-announced
beacon with `zk-kit finalize`. The result is a new key and therefore a new circuit id,
`score-over-v2`, registered alongside this one with ceremonyContributions = 2. A
key is never swapped in under an existing circuit id.

## Result

| | |
|---|---|
| verifyFromR1cs (r1cs + phase-1 file + zkey) | OK |
| Circuit hash (snarkjs) | `2ffb4db89c14db7d50b38b66844a81b7673f226be19641bcd1334038619a62d9eaddf158806d37e918bd7e930d30f9f0710be58c3f932c389eca6500c5640297` |
| `score-over-v1.zkey` | 170,609 bytes, sha256 `7abf10f83a5b79862d0c8536fbbb0eeaca840303759638c803e20d173b7930cf`, blake2b-512 `589ea737dd0c55f2b414e133aa2e49a7d3241eaaa976af96cd4b13fb7c6b40e45dd41766be835970d0e2507f014636168c1b115f01e6e53ba06ebcd7d0b0c0fa` |
| `score-over-v1.r1cs` | 120,388 bytes, sha256 `001fd51225e47299795cdc40da2b78ed86e1a15b55d9fc1441766330e663cff2` |
| `score-over-v1.wasm` | 1,752,528 bytes, sha256 `fd04b1f084c664e6755a7625db061e35c235146b12e385a75ad630d537f0596c` |
| vkHash | `0xa67ad431ce9e0ec172c16e12b7040d05cf5b55fec71144203008d59ff638fa37` |
| Verifier.sol runtime keccak256 (solc 0.8.24, optimizer 200, paris) | `0x2d9c8c141d415cf0848b4f9b7c6d3b9326eb57ec2ea48a9b88bbe9a3fa720da3` |

## Check it yourself

```sh
npm install /path/to/zk-kit          # or: npm install snarkjs@0.7.6 and use snarkjs directly
npx zk-kit ptau --power 9 --public --out ppot_0080_9.ptau   # compare blake2b512 above
npx zk-kit verify-ceremony --r1cs score-over-v1.r1cs --ptau ppot_0080_9.ptau --zkey score-over-v1.zkey
# prints: zkey VALID, then #1 Super Wallet (SeoulLabs) phase-2 contribution: 79ac91b94989b077...
#                             #2 Xphere mainnet block 49689564 beacon [beacon f881b8862fb95d63..., 2^10 iterations]
```